[Bug releng/6491] New: need runtime-analysis tool to extend blacklist

[Bug releng/6491] New: need runtime-analysis tool to extend blacklist

[fche at redhat dot com]

As seen in bug #6487, new kernel-side code called indirectly from probe handlers
via the runtime can cause deadlocks and whatnot.  It may be nice to have a script
that searches the external-reference/undefined-symbol chain starting from the
systemtap probe module, and a kernel build tree (individual compilation unit .o
files).  If only it could follow the undefined reference chain on a per-function
basis, the transitive closure could give us a pretty good blacklist suggestions.

(given an unresolved external function, find object file that defines it,
"objdump -dr" it to find the functions that it calls, then recurse).

(roland: your ideas regarding encoding the static call graph into dwarf would
be handy if ever implemented)

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           Summary: need runtime-analysis tool to extend blacklist
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: releng
        AssignedTo: systemtap at sources dot redhat dot com
        ReportedBy: fche at redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=6491

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[Bug releng/6491] need runtime-analysis tool to extend blacklist

[mhiramat at redhat dot com]

------- Additional Comments From mhiramat at redhat dot com  2008-05-07 21:27 -------
(In reply to comment #0)
> As seen in bug #6487, new kernel-side code called indirectly from probe handlers
> via the runtime can cause deadlocks and whatnot.  It may be nice to have a script
> that searches the external-reference/undefined-symbol chain starting from the
> systemtap probe module, and a kernel build tree (individual compilation unit .o
> files).  If only it could follow the undefined reference chain on a per-function
> basis, the transitive closure could give us a pretty good blacklist suggestions.

Some functions called from probe 'module' may be safe. I think only functions
called from probe 'handlers' will cause problems.

> (given an unresolved external function, find object file that defines it,
> "objdump -dr" it to find the functions that it calls, then recurse).

cscope will help you trace call graph.

Thanks,

-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=6491

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[Bug releng/6491] need runtime-analysis tool to extend blacklist

[fche at redhat dot com]

------- Additional Comments From fche at redhat dot com  2010-04-17 15:30 -------
This approach may not yield useful blacklist additions.  Most of the
recent additions were not due to unexpected reentrancy, but some other
mysterious misbehavior.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |WONTFIX


http://sourceware.org/bugzilla/show_bug.cgi?id=6491

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